sera marin basic salt 20Kg The new formula of sera sea salt ensures crystal clear conditions in saltwater. Its excellent homogeneity and uniform grain size rapidly dissolves to form crystal clear saltwater. It has natural GH and KH values, and is rich in calcium and magnesium in a biologically correct ratio. The natural buffer system in sera sea salt maintains the pH value precisely and ensures that it stays within the correct range. Through a specially developed process, sera sea salt contains trace elements that keeps them dissolved permanently. Therefore they remain available for a long time. sera sea salt does not contain any artificial ingredients that activate the protein skimmer, and it is free from nitrates, silicates and phosphates.